Study On Wave Time History Superposition Method Of Seismic Body Wave And Its Influence On Slope Response

Seismic dynamic action is the main precipitating factor of slope failure,and it has very important research value.At present,in seismic dynamic response research of slopes,seismic oscillations with a single vibration direction are mostly used,and there is no mature analysis method for the excitation of actual seismic fluctuations with different seismic phases.According to the basic model of earthquake disaster:seismic source-propagation path-engineering site,comprehensive consideration of source characteristics,source location and relative azimuth of slope,and formation media of seismic wave propagation,etc.,determine the seismic phase of the seismic wave arrival time reaching the slope site.constitute.In this paper,the excitation of the slope is studied by using the time series of seismic waves that are superimposed by two kinds of P-wave and S-wave seismic waves.The superposition method of the time history of the stress wave of multi-seismic seismic waves is analyzed to discuss the multi-seismic seismic wave.The analysis method developed by Cheng on the slope excitation is as follows:(1)Study on the distribution characteristics of simplified longitudinal and transverse wavefields of typical sources;(2)The influence of formation media on seismic wave propagation in the study area;(3)A Study on the Way of Exciting Slope with Multi-seismic Superposition Seismic Wave Duration.Based on the analysis of seismic oscillation analysis method for multi-seismic earthquakes,based on the morphology and stratigraphic structure of representative slopes in Tianshui area,a simplified slope model was established.Using FLAC~3DD software,the dynamic response of slopes under multi-seismic superposition seismic waves was studied.Through the analysis of the critical seismic acceleration of the slope failure corresponding to the excitation of different superimposed seismic waves,the following points are obtained:(1)Corresponding to the excitation effect of the superposition and combination of seismic waves of different earthquake phases,the shape of the destructive plastic zone of the same slope is significantly different from that of the critical ground motion acceleration.The P+SH seismic phase combination has the strongest effect on the disturbance of the slope,and it is most likely to make the slope Landslide instability damage occurred.(2)Under different longitudinal and shear wave amplitudes than seismic waves,there is no significant difference in the plastic zone distribution of the slope,but the critical ground motion peak acceleration of the slope failure decreases with the proportion of the P wave phase amplitude and the amplitude of the SH phase amplitude.Increase and gradually decrease.(3)When the source is shallow and near,the focal acceleration and epicentral distance have significant influence on the critical acceleration of the slope failure.With the change of the location of the source,the critical acceleration will change significantly.(4)The incident direction of the seismic wave has a great influence on the shape and distribution of the plastic zone in the slope,and also has a significant impact on the critical seismic acceleration of the slope failure.Among them,when the incident azimuth is 180°,the slope is the most dangerous;when the incident azimuth is135°,the slope is the safest.